Preheat Oven: Preheat oven to 350°F (175°C). Grease and flour a 9-inch cake pan.
Dry Ingredients: In a bowl, whisk together flour, baking powder, and salt. Set aside.
Cream Butter & Sugar: Beat butter and sugar until light and fluffy (3-4 mins).
Add Eggs & Vanilla: Beat in eggs one at a time, then add vanilla.
Alternate Mixing: Gradually mix in dry ingredients and milk (starting and ending with flour).
Bake: Pour batter into the pan and bake for 30-35 mins (until a toothpick comes out clean).
Cool: Let cool in the pan for 10 mins, then transfer to a wire rack.